A stretch of highway, Segment X, has no traffic signals and comprises

Question

A stretch of highway, Segment X, has no traffic signals and comprises three speed zones: One with a speed limit of 55 miles per hour (mph) followed by a 75-mph zone and a second 55-mph zone. Leslie is at a certain point on Segment X, driving at a speed she will exactly maintain until after she has reached the end of Segment X and has entered the next highway segment. Is she driving faster than 55 mph?

(1) Leslie’s speed is at least 5 mph below the speed limit that currently applies to her.

(2) Leslie will reach the end of Segment X without ever exceeding any speed limits.

(1) Leslie’s speed is at least 5 mph below the speed limit that currently applies to her.

(2) Leslie will reach the end of Segment X without ever exceeding any speed limits.

gmatophobia · Answer

In Segment X, the strip of the highway segment that has a speed limit of 75 mph lies in between two strips each of which has a speed limit of 55 mph.

Representation of Segment X

--- 55 mph ---|--- 75 mph ---|--- 55 mph ---

We are also given the fact that Leslie is at a certain point on Segment X, driving at a speed she will  exactly maintain until after she has reached the end of Segment X

The question requires us to find whether Leslie is driving faster than 55 mph.

Inference : We know that Leslie will maintain the same speed until she has reached the end of Segment X, hence unless she plans to overspeed in any of the three sub-regions of Segment X, she must be driving at a speed less than or equal to 55 mph.

Statement 1

(1) Leslie’s speed is at least 5 mph below the speed limit that currently applies to her.

Let's assume that Leslie is driving in a region of Segment X that has a speed limit of 75mph. Statement 2 provides us with the information that Leslie’s speed is at least 5 mph below the speed limit that currently applies to her. So Lisa can be driving at any speed less than or equal to 70 mph.

This information is not sufficient to answer the question "Is she driving faster than 55 mph?".

For example, if Leslie's current speed is 60 mph, the answer to the question "Is she driving faster than 55 mph?" is Yes. However, if Leslie's current speed is 55 mph, the answer to the question "Is she driving faster than 55 mph?" is No.

Statement 1 is not sufficient. We can eliminate A and D.

Statement 2

(2) Leslie will reach the end of Segment X without ever exceeding any speed limits.

We know from the question stem that Leslie will maintain her current speed until she crosses Segment X. As the third region of Segment X has a speed limit of 55 mph, Statement 2 provides us with the information that Leslie will not exceed that speed limit.

Hence, in whatever region of Segment X Leslie is currently driving, the current speed does not exceed 55 mph.

The answer to the question "Is she driving faster than 55 mph?" is No.

Statement 2 is sufficient.

Option B

Archit3110 · Answer

Three segments are 55,75 &55 MPH

#1
Leslie’s speed is at least 5 mph below the speed limit that currently applies to her.
CAN BE 50,70 or any value
Insufficient as range is 50 to 70 Insufficient 
#2
Leslie will reach the end of Segment X without ever exceeding any speed limits
By end is limit less than 55mph but its not confirmed what segment is she at
From 1&2
Speed can be less than or more than 55 mph depending on Segment she is at
IMO E

Posted from my mobile device

gmatophobia · Answer

You are missing the fact that Leslie will maintain the exact speed until she has crossed Segment X. Hence, if her current speed is more than 55 mph(assume she is driving in the region that has speed limit of 75 mph), then she will maintain that speed in the last region, which has speed limit of 55 mph, as well. However, Statement 2 puts forward an additional information that Leslie will not exceed speed limits in Segment X. Hence, the maximum speed that Leslie can drive is 55 mph. This is regardless of whatever region of Segment X she is currently driving now.

Posted from my mobile device

Archit3110 · Answer

I agree to your logic
But question has asked
Is she driving faster than 55 mph?
How can we determine which segment is she at from this.
Segment X has three divisions 55---75---55

Posted from my mobile device

You are missing the fact that Leslie will maintain the exact speed until she has crossed Segment X. Hence, if her current speed is more than 55 mph(assume she is driving in the region that has speed limit of 75 mph), then she will maintain that speed in the last region, which has speed limit of 55 mph, as well. However, Statement 2 puts forward an additional information that Leslie will not exceed speed limits in Segment X. Hence, the maximum speed that Leslie can drive is 55 mph. This is regardless of whatever region of Segment X she is currently driving now.

gmatophobia · Answer

While I have already addressed the highlighted question in my previous responses, let me rephrase it for clarity.

From the given question premise, we establish that Leslie will maintain her current speed limit. Statement 2 provides additional insight, indicating that "Leslie will reach the  end  of Segment X  without ever exceeding any speed limits ."

Considering that the last division (region) of Segment X has a speed limit of 55 mph, Statement 2 ensures that Leslie's speed does not surpass 55 mph. This holds true regardless of the division she is currently driving in—whether it's Division 1, Division 2, or Division 3. The key point is that her current speed limit remains less than or equal to 55 mph. This certainty arises from her commitment to maintaining the same speed limit in Division 3. Any speed exceeding 55 mph in a prior division would result in her surpassing the 55 mph limit in Division 3 of Segment X.

Therefore, Option B is sufficient to definitively answer "No" to the question: "Is she driving faster than 55 mph?"

chetan2u · Answer

Great question from GMAC

Question statement:  Three speed zones within Segment X, 55 - 74 - 55 mph. Leslie is at a certain point but will continue with that speed till the end of segment X.
So Leslie is in some zone ans she will maintain that speed till end. If she is travelling at 60 mph, she will continue with it till the end of the segment X. If she is travelling at 100 mph or 10 mph, 55 mph zone, she will continue with it till the end of the segment X.

(1) Leslie’s speed is at least 5 mph below the speed limit that currently applies to her.
If she is in 55mph zone, so she is travelling at a speed less than 50 mph. 
But if she is in 75 mph zone, she will continue at a speed less than 70 mph, which could be greater than 55 mph.
Insufficient

(2) Leslie will reach the end of Segment X without ever exceeding any speed limits.
We know she has to surely cross the last stretch, that is 55 mph zone. If she was travelling at a speed greater than 55 mph, she would surely cross the third stretch at that speed and thus, cross the speed limit. But, she never crosses that limit. SO, surely she is travelling at a speed that at the most 55 mph.
Sufficient

B

yazlal25 · Answer

This is a really tricky one. The question says ' she will exactly maintain until after she has reached the end of Segment X ' which means she is going to drive at a constant speed through the segment X (no matter which zone she starts in). Now, I made this assumption by default that her speed cant then be more than 55 because she will have to pass the third zone with 55mph as the limit in order to exit segment X. My mind assumed she wont exceed speed limits by default, but this is the trick. You cannot assume that Leslie is a responsible citizen!

Only when the problem statement explicitly states she doesnt exceed any speed limites (like in statement (2)), you can conclude that she is riding at 55 or less. Now the 1st statement - if you dont assume Leslie is a responsible citizen, She could be driving at 75 - 5 or 55 -5 depending on which zone she is in - which makes it insufficient. Hence answer is B. Conclusion - Dont assume GMAT throws cases of responsible citizen in all its questions!

KarishmaB · Answer

|_________________55_________|_______________75______________|_________________55____________|| This is what the highway segment X looks like with the speed limits. Currently she is at a speed that she will maintain till the end of this stretch. Question : Is she driving faster than 55 mph? Note that we cannot assume that she will stick to speed limits. People do routinely break speed limits and she may do so too. If we were to assume that she will stick to speed limits, then we do not need either statement. In that case, without any stmnt, we know that she must be going at 55 or below (def not above 55) because the last stretch limit is 55. So wherever she is right now, if she maintains that speed till the end without every going beyond the limit, her speed is definitely not more than 55. Hence you know that you have data missing - will she stick to the speed limit? (1) Leslie’s speed is at least 5 mph below the speed limit that currently applies to her. Her current speed could be 50 or below or 70 or below. No info on whether she will stick to speed limit. Not sufficient. (2) Leslie will reach the end of Segment X without ever exceeding any speed limits. Perfect. If she will not exceed any speed limits, we KNOW that she is going at 55 or below right now. So we can answer the question asked with a "DEFINITE NO" Sufficient. Answer (B) Here is another interesting discussion on a non Math DS question: https://youtu.be/yzeh388tkLQ

aronbhati · Answer

Hi Sir,

in statement: 2 if she drives 1st and 3rd portion of segment then it is fine that she is not driving faster than 55 but during 2nd portion of segment she is driving at 75 MPH means she is driving more than 75 MPH

Gmat860sanskar · Answer

Hello Aron,

I think you may have not inferred this line properly : " Leslie is at a certain point on Segment X, driving at a speed she will exactly maintain until after she has reached the end of Segment X and has entered the next highway segment." This says that Leslie will maintain same speed throughout the journey.

So statement 2 says : Leslie will reach the end of Segment X without ever exceeding any speed limits.

So think what would be the speed, which she need to drives at, for which she don't have to break any speed limit in consideration with our inference that she have to maintain same speed throughout the journey. obviously, it would be less than 55, because if not, she will break the limit in 2 of the 3 zones.

That's how we can definitely answer the question with statement 2, that's why our answer here is B.

A stretch of highway, Segment X, has no traffic signals and comprises

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GMAT Data Sufficiency (DS) Questions

A stretch of highway, Segment X, has no traffic signals and comprises

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